影响刮板流量计计量误差的温度因素分析

京唐输油处采用美国Smith刮板式流量计对油品进行计量,当不同油品性质相差较大,或者有冷空气侵袭计量站地区时,刮板流量计计量出现很大误差,扰乱了企业的正常输油和安排。实验中对油品物性尤其是粘度进行了测量,分析了物性中粘度的影响是最大的。其次,通过现场不同月份对流量计的标定数据,分析了外界的环境温度对计量影响不可忽视。通过实验研究,油品粘度和环境温度对刮板式流量计计量精度起主要影响,并给出了建议。     

高密度聚乙烯熔体剪切粘度的双因素数学模型—计算机求解及模拟

本文用聚合物材料工程中表示熔体粘度的双因素数学模型,lgη=A_0+A_1lgγ+A_(11)(lgγ)~2+A~2T+A_(22)T~2+A_(12)Tlgγ根据实验数据来拟合高密度聚乙烯的熔体粘度。对此模型采用了线性化方法,然后以多元逐步回归求出回归系数,并用非拟合点的实验数据与模型的模拟值进行了比较,结果表明此模型对于高密度聚乙烯是适宜的。整个计算过程是采用我们为紫金-Ⅱ徽型计算机编制的BASIC语言的毛细管流变仪数据处理系统进行的,可打印出计算结果及流变性质关系图。     

涡轮流量计变粘度流量计算与校准方法研究

为探索涡轮流量计在变粘度工况下的流量计算和校准方法,研究中利用变温航空润滑油流量标准装置对10支涡轮流量计在多个粘度点下进行校准试验,对各粘度下流量计仪表系数进行数据分析。以涡轮流量计理论模型为基础,提出以双指数衰减函数对仪表系数进行拟合计算的方法,各流量计拟合曲线的r2值都优于0.99,且各粘度点流量测量结果误差都小于1%。研究中进一步提出通过关键点雷诺数确定流量选点的校准方法,关键点拟合结果与全数据拟合结果两者差别基本都小于±0.33%。建议对变粘度工况涡轮流量计流量计算和校准方法进行深入试验研究,进一步验证上述方法可行性。     

油气集输过程中压降变化规律研究

本文研究了高含水期油气集输过程中流型以及压降变化。通过实验测得数据修正,并对油气集输管道的流型计算结果与实测流型进行了比较。同时根据实验数据利用最小二乘法对分气相折算系数经验公式进行了拟合修正,对拟合后公式计算井口压降结果与拟合前井口压降计算结果、实测压降以及模型计算结果进行了比较。研究证明,修正后的流行图以及冲击流压降模型计算结果与实测数据相吻合,误差较小,适合采油厂工程应用。     

油气集输过程中压降计算与变化规律研究

本文研究了高含水期油气集输过程中流型以及压降变化。通过实验测得数据修正，并对油气集输管道的流型计算结果与实测流型进行了比较。同时根据实验数据利用最小二乘法对分气相折算系数经验公式进行了拟合修正，对拟合后公式计算井口压降结果与拟合前井口压降计算结果、实测压降以及模型计算结果进行了比较。研究证明，修正后的流行图以及冲击流压降模型计算结果与实测数据相吻合，误差较小，适合采油厂工程应用。     

[C_4mim][BF_4]粘度的模拟与实验

为了研究离子液体的粘度特性,以1-丁基-3-甲基咪唑四氟硼酸盐([C4mim][BF4])离子液体为研究对象进行模拟计算与实验测试.基于分子动力学原理,编译了离子液体粘度的模拟计算程序,对[C4mim][BF4]离子液体完成了粘度模拟计算.搭建了粘度测试系统,进行离子液体的粘度测试.通过实验数据与模拟数据的对比,验证了模拟结果的准确性.另外,根据模拟粘度值的拟合曲线,分析了离子液体粘度的变化规律.同时,通过与水粘度的比对研究,阐述了[C4mim][BF4]离子液体的粘度特点.     

混合气候地区极值风速分析方法研究

在混合风气候地区,不同类型风气候（如台风、良态风）的极值风速概率分布特性各不相同,如果直接采用单一概率分布模型对混合极值风速进行拟合,往往会造成较大的分析误差。目前常采用将台风和良态风数据分离后分别分析的方法进行极值风速分析,但这种方法在分析良态风时存在难以将台风记录从气象部门长期观测数据中分离出来的问题,在台风蒙特卡罗模拟研究中存在台风参数概率分布信息收集困难的问题。该文基于混合函数构建混合风气候地区极值风速的概率密度函数,采用加权最小二乘法拟合分布函数和权重函数的参数,并对各参数进行优化得到更为精确的计算结果。最后采用蒙特卡罗模拟结果和长期观测数据验证了该文方法的准确性和实用性。     

潜热型纳米流体粘度特性的实验研究

实验测量了潜热型纳米流体TiO2-BaCl2-H2O的粘度,分析了纳米粒子体积分数和温度对纳米流体粘度的影响.实验结果表明,在BaCl2水溶液中添加纳米TiO2会增加其粘度,且随着粒子浓度的增加,粘度增加越显著;粘度随温度降低而升高.潜热型纳米流体TiO2-BaCl2-H2O的粘度不随剪切应力的变化而变化,表现为牛顿型流体的流变特性.基于实验数据,建立了潜热型纳米流体TiO2-BaCl2-H2O粘度的计算模型,模型预测值与实验值的误差在2％以内.     

水平微翅管内二元混合制冷剂流动沸腾阻力特性研究

对非共沸混合工质R32／R134a在水平微翅管内流动沸腾阻力特性进行了实验研究,分析了影响压特性的一些因素,讨论了混合物在水平微翅管内流动沸腾的流动阻力特点和规律。通过对试验数据的拟合,按分相模型计算了加速阻力,并建立了预测摩擦阻力的关联式,计算结果与实验较吻合。     

坑道口部内爆炸冲击波传播速度规律的数值分析

准确计算坑道口部内爆炸条件下冲击波传播速度的变化,是确定坑道内主动消波设备时间响应指标的关键.为此,基于AutoDyn进行5种不同工况的坑道内爆炸计算.采用量纲分析构建了冲击波传播速度的工程模型,通过对数值计算结果的拟合确定了模型的系数.与坑道化爆实验的实测值进行分析比较表明,所拟合的坑道内冲击波传播速度的经验模型最大误差为15％,作为一种工程方法而言具有较强适用性.     

An automotive engine oil viscosity sensor

For the evaluation of the condition of automotive engine oil, the oil's viscosity is one of the most important parameters. Using microacoustic viscosity sensors, an oil-viscosity measurement can be performed on-board. In this contribution, we discuss the behavior of the viscosity of engine oil, its temperature dependence, and the resulting representation in terms of output signals of microacoustic viscosity sensors. These considerations are illustrated by means of measurement results obtained for used oil samples, which have been obtained from test cars and fresh oil samples out of different viscosity classes. Finally, the detection of the viscosity increase due to soot contamination is demonstrated.     

Pressure-viscosity coefficient of a refrigerant-oil mixture: Coefficient pression-viscositéd'un mélange frigorigène-huile

A coaxial cylinder viscosimeter has been used to determine the pressure-viscosity coefficient of a pure refrigeration oil and of a mixture of refrigerant and oil at gauge pressures up to 15 MPa. The test fluid, Gargoyle Arctic oil 300, is a naphthenic-base oil. The refrigerant was R22, chlorodifluoromethane, which is a commercially important refrigerant. In a gap apparatus the refrigerant-oil mixture has been visually inspected at different pressures. Two different mechanisms are involved in the refrigerant-oil mixture: the change in solubility with pressure and the change in viscosity with refrigerant concentration. If the mixture is pressurized with excess refrigerant available then the concentration of refrigerant will increase with increasing pressure and therefore the viscosity will decrease. If the concentration is kept at a constant level then the viscosity will increase with pressure. The results from the cylinder viscosimeter showed that the viscosity increase with pressure for the mixture was almost the same as for the pure oil.     

双筒式液压减振器阻尼力建模与灵敏度分析

为提高减振器阻尼力输出的准确性及减振器性能可靠性,定量分析双筒式液压减振器尺寸参数及其公差、油液黏度等对阻尼力的影响。根据阻尼力的产生机理,建立了减振器复原行程中复原阀开启前、后的阻尼力模型和压缩行程中压缩阀开启前、后的阻尼力模型,利用MATLAB仿真得到了其示功图和速度特性图,并通过台架性能试验进行了验证。考虑到阻尼力模型的复杂性,采用ANSYS中的Design Exploration模块,利用响应面法得到了减振器各个参数的灵敏度,并针对油液黏度、阀系开启高度等影响较大的参数,考虑其随机性,利用蒙特卡洛抽样方法得到了减振器阻尼力的分布,从而为双筒式液压减振器的设计提供了依据,为进一步研究减振器的阻尼力退化及寿命评估奠定了基础。     

Damping force modeling and sensitivity analysis of double-tube hydraulic damper北大核心CSCD

In order to improve the accuracy of the damping force's output and performance reliability of the damper, the influence of size and tolerance of the double-tube hydraulic damper and the viscosity of the oil on the damping force is quantitatively analyzed. According to the generation mechanism of the damping force, the damping force model before and after the recovery valve opened in the recovery stroke and the damping force model before and after the compression valve opened in the compression stroke were established. By using the MATLAB simulation, the indicator diagram and speed characteristics diagram were obtained, and the performances were verified by bench test. The sensitivity analysis of the different parameters was done by using the Design Exploration module of ANSYS considering the complexity of model. Based on the randomness of the oil viscosity, the opening degree of the recovery (compression) valve which has more influence on the damping force, the prior distribution of the damping force was calculated by using Monte Carlo method. The results show that the damping force is distributed normally, and the method provides a basis for the design of double-tube hydraulic damper.     

基液黏度对草酸氧钛电流变液性能的影响

以草酸氧钛纳米颗粒为分散相,以不同黏度的二甲基硅油(运动学黏度为10 cSt、50 cSt、100 cSt、500 cSt和1000 cSt)为基液制备电流变液,测试其剪切屈服强度、零场黏度、电流变效率、响应时间及沉降稳定性,研究了基液黏度对草酸氧钛电流变液性能的影响。结果表明,以50 cSt二甲基硅油为基液的电流变液具有最佳的电流变效率,以100 cSt二甲基硅油为基液的电流变液具有最短的响应时间和较高的沉降稳定性。其机制是,较高的基液黏度可提供较大的黏滞阻力,但易引起颗粒的团聚。     

铜箔轧制润滑状态与表面质量的研究

使用不同运动粘度的轧制油和在不同道次压下率条件下进行了铜箔冷轧实验。利用激光扫描共焦显微镜(LSCM)和表面粗糙度仪对铜箔轧后表面形貌进行了表征,得到铜箔轧制变形区膜厚比和摩擦系数。研究了轧制油运动粘度,道次压下率对铜箔轧制变形区油膜厚度、表面粗糙度和前滑值的影响,并从膜厚比、摩擦系数和表面质量3个方面对不同润滑条件下铜箔轧制变形区的润滑状态进行了界定。结果表明,轧制油运动粘度γ40≤15mm2/s时,膜厚比λ→0,摩擦系数μ≈0.1～0.2,属于边界润滑状态,表面质量较好;道次压下率20%<ε≤60%时,膜厚比λ→0,摩擦系数μ>0.1,属于边界润滑状态,表面质量较好。为得到高表面质量的铜箔,轧制油运动粘度应控制在10mm2/s左右,道次压下率控制在30%左右,也即,使铜箔轧制润滑状态控制在边界润滑状态为最佳。     

一种黏温修正方法的研究与建立

为提高非标准环境实验室内工作黏度计校准检测精度,依据实验定值的黏温数据,系统地分析了所选精制石油产品和精制甲基硅油标准黏度液的黏温特性.选择优化了Walther方程、Arrhenius方程,采用20、25℃定值结果作为参考点,对精制石油产品标准黏度液的运动黏度-温度、精制甲基硅油标准黏度液的动力黏度-温度建立了黏温修正...     

Formation of water-in-oil emulsions and application to oil spill modelling

Water-in-oil mixtures were grouped into four states or classes: stable, mesostable, unstable, and entrained water. Of these, only stable and mesostable states can be characterized as emulsions. These states were established according to lifetime, visual appearance, complex modulus, and differences in viscosity. Water content at formation was not an important factor. Water-in-oil emulsions made from crude oils have different classes of stability as a result of the asphaltene and resin contents, as well as differences in the viscosity of the starting oil. The different types of water-in-oil classes are readily distinguished simply by appearance, as well as by rheological properties. A review of past modelling efforts to predict emulsion formation showed that these older schemes were based on first-order rate equations that were developed before extensive work on emulsion physics took place. These results do not correspond to either laboratory or field results. The present authors suggest that both the formation and characteristics of emulsions could be predicted using empirical data. If the same oil type as already studied is to be modelled, the laboratory data on the state and properties can be used directly. In this paper, a new numerical modelling scheme is proposed and is based on empirical data and the corresponding physical knowledge of emulsion formation. The density, viscosity, saturate, asphaltene and resin contents are used to compute a class index which yields either an unstable or entrained water-in-oil state or a mesostable or stable emulsion. A prediction scheme is given to estimate the water content and viscosity of the resulting water-in-oil state and the time to formation with input of wave height.     

容积法建模应用于单相流体网络的动态仿真

从模块化建模的角度出发，针对在暖通空调系统中常见的单相流体网络，对一些关键部件进行合理假设、划分并建模，通过将网络节点抽象成小容积环节并建立容积模块，实现模块化建模。仿真结果表明，采用容积模块可以克服传统的迭代算法缺陷，大大减小在线计算量，高效实现动态仿真。     

复杂形状液体包装容器3D容积刻度线的设计与研究

以ProE软件为平台,研究了复杂形状容器的体积与高度的变化规律,并以食用油桶为例,利用ProE行为建模模块中的"UDA"分析功能、Pro/Program模块中的程序编辑以及曲面模块,在容器表面智能化地刻制3D刻度线以及标示容积大小的3D文字,有效地解决了容器容积的标示问题,保证了容器容积的标示精度,提高了刻度容器的设计与加工的效率。该方法可应用于复杂容器容积的计算和刻度线的设计制作。